According to a police report obtained by DVB, the Indonesian prison brawl, which broke out on 5 April killing eight Buddhists and injuring 15 Rohingya men, was not caused by an argument over religious violence in Burma as previously reported.

Instead the report pins the blame on “several incidents” of sexual violence perpetrated by Burmese Buddhists against Rohingya women, including two brutal gang rapes, which the authorities failed to investigate. A third woman was sexually assaulted by two men after taking a bath next to her room at the Belawan detention centre in Medan, Sumatra island.

Although a Rohingya leader quickly reported the incidents to officers at the detention centre, the perpetrators were “only reprimanded and slapped” on the cheek, according to the police report.

A gang of eight Buddhists, identified as “illegal fishermen”, then threatened the Rohingyas and “an unequal quarrel broke out”, in which knives, wooden rods and screwdrivers were used by the two groups to attack each other. All five men, implicated in the three cases of rape and sexual assault, were killed in the brawl.

The new report contradicts previous accounts, which suggested that the Rohingyas launched an attack against the Buddhists after seeing images of recent anti-Muslim violence, which swept through central Burma in late March, claiming over 40 lives.

It follows two bouts of vicious clashes between Rohingya Muslims and Buddhists Arakanese in western Burma last year, in which over 125,000 people were displaced.

The Rohingyas detained on Sumatra Island in Indonesia were described by police as “asylum seekers” with “long-standing resentment against Buddhist citizens of Myanmar [Burma] as a result of atrocities against Rohingya people committed by other Myanmar citizens.”

Rohingyas are denied citizenship and basic rights by the Burmese government and are considered one of the world’s most persecuted minorities by the UN.

Since last year’s violence in western Burma, which primarily targeted Muslim villages, more than 15,000 Rohingyas have fled the country. The refugees, including women and children, often makes the perilous journey by sea on rickety boats, in the hopes of reaching other Muslim countries, such as Indonesia or Malaysia.

The Burmese government has demanded a full investigation into the violence and called on the Indonesian authorities “to pay special attention” to the protection of its citizens.

Police forces have named 20 Rohingya asylum seekers as suspects in the violence, including five 16-year-olds and one 15-year-old. According to the Jakarta Post, the suspects are accused of “conducting collective assault and torturing” and face a maximum sentence of 12 years imprisonment if convicted.

The report also called for an increase in security at Indonesian detention centres, as well as the segregation of Muslims and Buddhists from Burma.

However questions remain over the future of the remaining Rohingya detainees, who may be returned to Burma unless they are granted asylum in Indonesia or a third country. The police report also reveals that the detention centre was crammed with over twice as many inmates as its capacity allowed.

The UN Refugee Agency (UNHCR) has appealed for calm and urged the Indonesian authorities “to take action to prevent further violence, including moving individuals into community housing as soon as possible”.

“If detention is used as a last resort, we advocate for vulnerable individuals like women and children to be housed separately,” UNHCR spokesperson, Vivian Tan, told DVB on Wednesday.